Transmission control system



Jan. 6, 1953 l.. B. FORMAN 2,624,210

TRANSMISSION CONTROL ASYSTEM Filed' July 24 ,1 1951 yratio drive whichis usually a Patented Jan. 6, 1953 2,624,210 TRANSMISSION CONTROL SYSTEMLouis B. Forman,

Chrysler Corporation,

Detroit, Mich., assignor to Highland Park, Mich., a

corporation of Delaware Application July 24, 1951, Serial No. 238,303

(Cl. Z4-472) 9 Claims.

This invention relates to motor vehicles and refers more particularly topower transmissions and control systems therefor.

My invention has particular reference to transmission control systemswherein the disengagegranted December 14, 1948, and Augustin J.

Syrovy et al. 2,490,604 granted December 6, 1949.

It has been customary. aS shown by the aforesaid patents, to provide ashiftable drive control element of toothed character arranged tointerengage with a second toothed drive control element after passingthrough a toothed blocker. Engagement occurs upon synchronism obtainingbetween the drive control elements subsequent to engine deceleration byaccelerator releasing movement, and the shiftable element is adapted tobe unloaded, :as described above, to facilitate its disengagement fromits companion drive control element.

The drive control elements are generally so arranged in lthetransmission that upon relative engagement under governor control at orabove a predetermined vehicle speed, there is provided a fast speedratio drive through the transmission, usually :a direct drive, and whenrelatively disengaged under governor control below a predeterminedspeed, or by kickdown means such as accelerator actuated switch meansoverruling the governor, there is provided another speed slower speedratio drive than the rst mentioned one.

Also customarily provided are prime mover or differential pressureservomotor means which may comprise a spring and a hydraulic or vacuumoperated motor having a movable piston, for controlling shift of theshiftable dri-ve control element through an associated shift rail orlever Isystem. In the case of the hydraulic system, vas

typified by the Syrovy et al. patent aforesaid, pressure fluid actingupon the piston will cause it to compress a disengaging spring and anengaging spring,

and build up suicient available force in the latter to move the shiftrail and by it the shit-table drive control element against its blockerand then into engagement with its companion drive control element whensynchronization of the drive control elements subsequently occurs.

In the case of the vacuum power system, as

typified by the Neracher et al. patent, vacuum is utilized to cause thepiston to compress a disengaging spring previously tensioned byoperation of the rod, the latter spring rin turn acting upon a lever toeffect movement of the shiftable element against its blocker and intosubsequent engagement with its companion drive control'element when thedrive co'ntrollelements obtain synchronism.

Transmission systems of the aforesaid typical character also usuallyinclude electromagnetically controlled v-alving for controlling venting(admission of atmospheric pressure) of the servo motor and operation ofthe piston such that when the motor is vented, the disengaging springactuates the piston to effect disengaging shift of the shiftable drivecontrolelement accompanied by ignition interruption, the latteroccurring as an incident to available lost motion operation of thepiston relative to the shift rail in Syrovy et al., and the piston rodrelative to the lever operating member in Neracher et al.

Customarily there is also provided an ignition interrupter switchoperated by movement of the piston in Syrovy et al. or by the piston rodin Neracher et al. Moreover, as in the above patents, there is kprovidedan electrical system intended to accommodate interruption of the engineignition only during the disengaging stroke of the piston, it being soarranged that even though the ignition interruption switch closes on thereturn (engaging) stroke, the ignition is not ordinarily grounded outbecause at such time neither of the parallel arranged kickdown andgovernor switches which are arranged in series with the ignitioninterrupter switch and in series with the valve solenoid in a parallelcircuiting is closed. Hence firing of the engine is not usuallyinterrupted during acceleration from vehicle standstill in the slowerspeed ratio drive.

Although the foregoing described arrangements have in general beensatisfactory, they have been open to one or more unforeseen conditionsof operation which it is desirable to avoid. In the arrangementdisclosed by Neracher etal. and Syrovy et al., especially where a higherresistor type of ignition harness has been employed, some lurching ofthe vehicle hasv been noticeable in vehicle operation during upshifts.It is believed that in a circuiting wherein actuation of the interrupterswitch places the ignition primary coil and the solenoid of the controlvalve in parallel circuits, the solenoid coil `of' a conventional clutchpedal I2.

Vbe any type incorporating positively delivered by the secondary at theplugs at the time of current ow thereto to be weakened. In thisconnection, it may be observed that under normal engine operation thehigher the engine R. P. M., the lower is the secondary volt-age, andsince the upshift takes place at a substantial R. P. M. the eiect of thelow impedance is to weaken the spark suihciently so that it may beunable to keep the engine running momentarily, as by causing the engineto misre. This condition can occur, for example, in the Neracher et al.arrangement and in the Syrovy et al. system when the relay coil of thelatter has a low impedance effect on the ignition primary.

An object of my invention is to provide an iinproved ignitioninterruption control adapted for use, for example, with a transmissioncontrol system of the types disclosed in the aforesaid patents and whichis capable of operation without weakening the ignition during thereturn, i. e., upshift stroke of the piston.

Another objeCt of the invention is to provide atransmission'shiftcontrol system having means 'for interrupting the engine ignition wheneffecting a downshift, but which system `inhibits weakening of theignition lspark intensity during the upshifting operations.

Still another object is to provide Va transmission shift control systemhaving means for momentarily interrupting the engine ignition wheneffecting disengagement of a pair of interengaged drivecontrol elements,and which system also 'provides means for preventing weakening of theignition spark intensity when eifecting engagement of said elements.

A speciic object is to provide a transmission shift control system ofthe above described character kwherein the valve operating s olenoid isprevented from 'acting as a parallel impedance to the primary winding ofthe/ignition coil if the interrupter switch is operated duringupshifting.

VOther objects and yfeatures of my invention will be apparent from thefollowing description wherein:

Figure. 1 is a diagrammatic plan view Yof the drvils power plant forth@vehicle;

Figure 2 'is an elevat'ionalrview partly in section of my invention'asapplied to a semi-automatic four-*speedk forward and reversetransmission, a part of the control system being schematicallyillustrated, the manually operable clutch sleeve being shown in itsforward or high rangeV position for starting the vehicle from rest, andthe power shiftable mechanism and power operable clutch sleeve beinglshown in the released position ofthe latter; and

Figure Sis an elevational View similar'to a portion ofthat'in Figure 2and showing the power shiftable clutch sleeve in its direct drive orengaged position andthepower shifting mechanism in the correspondingposition.

In thejdijawings in which similar numerals indicate similar parts o fthe structure, Figure 1 illustrates a typical motor vehicle power planthaving a conventional engine A for transmitting power through apropeller shaft ID to drive the rear ground wheels II. In the housing Bthere may be provided a uidA power transmitting device, such as a fluidcoupling karranged in tandem witha master friction clutch of knowntype,` the latter being releasable to uncouple the engine from thetransmission by operation of the housing B is a transmission C which mayengageable Rearwardly' drive control elements of a character usuallysubject to substantial thrust or torque load in operation, the latterconditions making the use of some form of unloading means desirable toinsure release of the drive control elements when a speed changerequiring disengagement of these elements is necessary.

The transmission C may be of various known types. For purposes ofillustration I have shown in Figure 2, a commercial form of four-speedand reverse countershaft underdrive transmission. This ytransmissioncomprises an input or driving shaft I3 which receives drive from theengine A by 'way of the clutch assembly B, and anoutput or driven shaftIt which is adapted to transmit drive to 'the propeller shaft Ie. Thedriving shaft I3 carries the main driving gear or pinion I5 and a set ofpositive jaw clutch teeth i which are adapted to. be engaged by theteeth of a jaw clutch sleeve D. As will be hereinafter seen, the sleeveD together with the clutch teeth It comprise relatively movable Vdrivecontrol elements for effecting stepup and stepdown vmanipulation `of thetransmission.

The clutch sleeve -D is slidably splined on teeth, not shown, of aforward hub portion of the high or third speed gear 22 which isrotatably journalledon the driven shaft M and adapted to be clutchedthereto through a jaw 'clutch sleeve F slidably splined on a hub, notshown, drivingly carried by the shaft I4fand i-nterengageabl'e with jawclutch teeth 25 carried by the -gear 22. The forwardshift ofsleeve D forclutching with vteeth IS is normally controllederimpeded by'a toothedblocker E whereby Aclutching is limited to synchronous relationship inthe speeds of `'rotation of gears I5 and 22 and, Vin the -particularconstruction illustrated, llimited to engine coast conditions obtainable byaccelerator releasing movement to secure-deceleration of the engine. TheblockerE is journalled on a conical surface, not shown, carried by theshaft lI3 against which it is frictionally urged by'a spring, also notshown, and has a limited lost motion connection with the s leeve D orgear 22 whereby it may rotate to place lits vteeth in blocking relationto the teeth of sleeve D whenever the gear YI -5 rotatably -leads orlags the sleeve D. When sleeve D moves Ypast the blocker 'E intoengagement with the clutch teeth It, the gears I5 and 22 are placed in atwo-'way direct drive relationship.

Gear 22, as stated above, is loosely journalled on the driven shaf-t I4whereas the pinion I5 is part -of the input shaft I3. Also looselyjournalled on the output shaft I is a low or rst speed gear 2'I having.jaw clutch teeth 28 engageable by the sleeve F. vAssociated Ywith thesleeve F on each side 'thereof is any commercial type of blockersynchronizers 29 such that clutch F' may be shifted vfrom a 4neutralposition -disengaged from'teeth 26 and 2t forwardly to -a high rangeposition to synchronously clutch shaft I with the high speed gear `r2?.througlh the teeth :it or rearwardly to a lowrange position tosynchronously clutch shaftV la with the low vspeed gear 21 at its teethV28. Manual shifts of the sleeve F are facilitated by release of themain clutch atB by means ofthe clutch pedal I2.

Gear 22is also adapted to be driven from gear I5 at a'speed-diiferentfrom 1:1 and'to this end I have shown a countershaft type one-wayreduction driving means between these gears, This drive comprises thecoaxially rotatablejcountershaft gear 3i] and cluster gear 3l wheels 32,3 3respectively. in constant mesh with gears I5, 22,' and 21 and anoverrunning roller clutch G operably interposed therein between the gear30 and cluster 3I. A stationarily mounted countershaft 34 provides ajournal support for the countershaft gears. Assuming the usual clockwiserotation of shaft I3 as viewed when looking from front to rear of Figure2, then overrunning clutch G will automatically clutch gear 30 andcluster 3l together when gear 36 is driven counterclockwise at a speedtending to exceed that of the cluster 3I andv automatically release thedrive between these gears to allow gear 30 to slow down below the speedof cluster 3I. For obtaining reverse drive an idler gear (not shown)having constant mesh with the gear 33 is shiftable rearwardly into meshwith a gear 35 fixed on shaft I4, the clutch F being then in its neutralposition disengaged from teeth 26 and 28.

As thus far described, it will be apparent that with the parts arrangedAas in Figure 2, sleeve F being then in high range position engaged withteeth 26, drive of shaft I3 will cause the output shaft I4 to be drivenat a reduction drive (third speed) through the gears I5, 30 overrunningclutch G, gears 32, 22 and sleeve F. Should the sleeve D be biasedforwardly during this reduction drive, blocker E will obstruct sleeve Din an intermediate position of its shift preventing ratcheting of itsteeth with the teeth I6. Howreleases-the engine throttle '4 ever, if thedriver control in the form of the usual accelerator pedal then, as willbe apparent, overrunning clutch G will allow gear I5 and teeth I6 toslowdown relaltive to the'sustained speed of gear 22 and when the speedof gear I5 reaches synchronism with that of gear 22, blocker E will moveto an unblocking position and allow sleeve D to move further forwardlyto clutch itsV teeth with teeth I6 to the position shown in Figure 3, toprovide the direct drive (fourth speed) clutch G continuing itsoverrunning operation. Upon return of i sleeve D to disengaged positionshown in Figure 2, followed by speeding up the engine, overrunningclutch- G will automatically engage to restore the reduction drive.

When clutch sleeve F is shifted rearwardly to low range position toclutch gear 21 to shaft I4 an overrunning slow speed drive (first speed)is transmitted from the shaft I3 to the shaft I4 by way of the gears I5,3D, overrunning clutch G, gears 33 and 21 and sleeve F. At such time asthe sleeve D is biased forwardly and the shaft I3 is allowed' to slowdown to permit the teeth I6 to become synchronized with the sleeve D,the sleeve will move past the blocker E and clutch with the teeth I6 toestablish a two-way relatively fast speed drive (second speed) in thelow range, which drivewill be from the shaft I3 through the sleeve D,gears 22 and 32,Y gears 33 and 21, and clutch F to the shaft I4, theclutch G overrunning by vreason of the cluster 3I rotating at a higherspeed forwardly than the gear 30.

It will be understood the driver may start the vehicle from rest in thelow range drive and subsequently shift to the high range incident tomomentary release of the master clutch and this either prior to orsubsequent to engagement of the clutch D. Most drivers, however, usually"start the vehicle from rest in the slow speed ratio of they high rangeand at a subsequent higher speed -obtain the automatic upshift to directdrive by momentary release of the accelerator pedal described above.

A more complete description of the transmission specifically illustratedin this application' and its method of operation l patent to A. J.Syrovy et al. 2,4.9IL604v aforesaid.

A speed responsive governor means O is provided to control forward biasof the sleeve D as well as rearward bias thereof as will be presentlymore apparent. Moreover, during drive in either second or fourth speedsreferred to above, a downshift to first or third speeds respectively maybe effected by way of overruling the governor O through driverdepression of the accelerator pedal M to substantially wide openthrottle position, which operation is referred to in greater detailbelow.

As seen in Figure 2,

is set forth in the I have illustrated a servo motor H by which toobtain power actuation of the clutchsleeve D, the motor here illustratedbeing of the pressure differential and spring operated type and in thedisclosed embodiment functioning by means of uid pressure. This motorpreferably comprises a cylinder 36 slidably receiving a piston 31. Thepiston slidably receives a shift rail or rod 38 mounted to operate inthe guideways 39 and 46. Fixed to rod 38 is a yoke 4I, a hub portion 42of which is secured to the rod 38 by means of a dowel screw 43. .The rod38 and yoke 4I constitute motion transmitting means S for the sleeveD,the yoke 4I as seen in Figure 2, having fingers 44 engaging in agroove 45 of the sleeve D to effect shift thereof.

A relatively small preloaded engaging spring 46 surrounds the rod 38 andis disposed between the hub of piston 31 and the hub 42 of the yoke-This spring 46 provides a lost motion thrust transmitting connectionbetween the piston 31 and the hub 42 of the motion transmitting means Ssuch that the piston 31 may be moved forwardly (to the left in Figure 2)for its power stroke, the piston 31 continuing its forward motion byfluid pressure even after the clutch D has been moved against theblocker E until the lip 41 ofthe piston uncovers the relief port 48 ofthe cylinder 36 whereupon forward movement of the piston 31 will cease,the fluid pressurebeing then expended through the relief port 48. Y

During the said forward movement of the piston 31 the engaging spring 46is compressed and urges the rail 38 through the hub 42 of the yoke 4Iforwardly thus in turn shifting the clutch sleeve D to its intermediateposition blocked by the blocker E. Subsequently upon synchronousrotation of the teeth I6 and sleeve D being obtained in response toaccelerator releasing movement, the sleeve D is moved through theblocker E into engagement with the teeth I6 of the drive pinion I5,which is its fully engaged upshifted position shown in Figure 3,establishing the previously described direct drive between the shaft I3and gear 22. V

A relatively large preloaded downshift or kickdown spring 49 is disposedbetween an abutment ring 50, located at the forward end of the cylinder36, and the piston 31. This spring serves to return the piston 31 andsleeve D from their Figure 3 positions to their downshifted ordisengaged position shown in Figure 2. It will be observed from Figure 3that the piston 31 when in its furthest forward position shown in thisgure uncovering the port 48 has moved further than the shift rail 38such that a gap 5I is created between the piston 31 and a shoulder 52rof the portion 53 of the shift rail. This gap 5I facilitates a lostmotion movement of the piston 31 relative to the shift rail 38 prior todisengaging movement of the sleeve D which can only commence followingabutment of the piston 31 with the shoulder 52. yAs previouslynoted,gfor- Atl'ieishaft 1.4 and "has itsrotor `6| .driven `byithatshaft, oilbeing drawn from the supply :source :6D through the conduit 62to the pump .inlet 63 ,and is deliveredunder pressureatthe pump .outlet64 .to ythe .conduit i'65 and-:then .to `the passage .6.6nundercontrol.ofa.ballvalve K. ,A relief valve, `generally 'designatedby:the numeral .61 and .pro-

vided .at .the .pressure side of the pumpbetween .theA outlet'f64 andthe ballzvalveKservesgas .agre- Y'lief .valvein'theJ event-the valveyK;is '.notopen in --normalfoperation of .the transmission. to :therebypermit pressure fluid ytrapped .behindthe piston '31'. tofbe.1 dumpedback vintogthe. transmission :sump

..60 through theconduit 61a.

'.When'the valve K iszclosed, oil under pressure -is 'forced Vdirectlyfrom the pump through the passage .66 tothe cylinderl whereit moves thepiston .31 vforwardly to :effect forwardmovement ofthe .shift railV38iin ,the manner described above wherebytheshift sleeve Disoperated'frcm its .disengaged'position -in Figure 2 to rits engaged`position of Figure 3 to establish ,second or'fourth speed ratio`drive.'dependingupon whether the .or with the thirdspeedgea-r 12-2.

Valve is `closedi by; bias ;of a valve spring t acting againsta bal1 ;69to close a discharge port llkopeningf-intofa passage n'Il idrainingtothe clutchF is engaged with-.the first speed gearw2'i sump or supply.source 160. ,'I-he valvefKrisactuated" to .zits open' .position undercontrol of an electromagnetic .device comprising 1a; solenoid L 1having-r 1a plunger Y'l 2 connected with the `movable coreofthesolenoid. :The valve- Krisclosed-.when

the solenoid L is decnergized. i The, spring 68 then actuatesftheballBeagainst a scatflto closeithe .-portf #370 and effects. inovementf ofthe L. solenoid plunger 12 to -its;r etracted position. 'Ifhe yalveK isopen-zwhengthe AsolenoidfL i is energized, v,the solenoid core thenmoving-,the plunger J2 idOwnf wardlygtofpush theball 69 off ttheAseat/.13- of port viiowffrom the pumpyQ throughithe conduit i5-,port75B, passage; 7 l back vtothe sump. 60.

Whenthe valve .5K is open;itisgimpossiblegior sufficient fluid pressureto idevelopin the passage 65 to move Athe pistoni-S'Iagainst the force.eX- erted by the piston hreturn springrllg which `then maintains thepiston at the extreme rearward position of.its.l capable movement..-Hencethe piston 31 isaCtuatedby-uidpressure .only, .to establishAsecond :and fourthV `speeds respectively at which-time Ythe valve. ;,K`isgclosed and ithe solenoid Ltdeenergized. 'Figure` 2;shows the; valveK in -fits' openzpositiongand thepistongal inpits `position,retracted-fby: spring ,49,...a

nd EFigure, 3

piston 31 inhits furthest.forwardposition under controlof thepressurefuid.

Energization .and deenergizationcfpthe solenoid I .1is` brought about byoperationfromone position to anotheroffeitherof .two control members,oneactuated. in lresponse to .vehicle .speed,. and

vthe other in response to--manipulationby anriver control member. One ofv these: control members is; the-governor O, and,"A thev other Ais 1 akickdown switchgenerally designated by theletter P. Suitlever projectionIa as ing movement. `operation of this switch maybe adjusted to able.electrical .circuit means nrovidedior effectuating the `control.operation .oitheggoycrnor andkickdown switchover -thesolenoid L. ,'Ihusa suitable sourceof electrical energy, for example, a storage battery 15 ,has one 'sidegrounded l.aset it by a Aconductor 'l'land its Aotherside Ac zAonriected .by ,a .conductor '18 :through .anammeter 1 9 totheignition switch Ylil). A conductor 8| connectsthe Aignition switch withone terminal 8 2 of `the .solenoid L, the 4other terminal v8i) of lthesolenoid being connected by a conductor@ with@ eier.- minal-.SS of a`switch cenerallyfdesienated bythe letter N .which is operated-bytheigovernor Q and .which has a second iennina11-dmieted$0 .a .groundAat by va conductor 39. Fronrthe Agc v ern;r .switch terminal .aondugtorzexteeds It@ a terminal 9| -of the -kickdown V.snap switch?,this switch having a second terminale? Vc.onrected)to `conductor switchbar .95 operatedby4 an,.finsulated slidingsleeve 96 of Athe governor .0,the switch ,being closed when meter 95 bridgesthe'timi- 1?@1585 and 37.The kickdown s 'wtch'rP is ofthe snap type and has a conductor .bar 91which .closes the same by bridgingthe terminals 9| `a`n`d Q2 of V thisswitch.

Thus by means of the governor switchNand .the kickdown switch P, two2parallel ground fcircuits are provided for the Ysolenoid L, the .gov-

ernor switch N opening at a .speed proportional .to vehicle speedestablished bythe drive connecreleased position.

The accelerator M is Ysuitably connected with the usual enginecarburetor throttle valve by means including linkage |03, v-Iilfl whichVserves to open and close theV throttle valve. Interposed in thethrottle valve operating linkageisa lever HB5 pivotally supported at |96and having spaced fingers or projections |i8, I l0 for operating theactuating nger I2 vof thesnap switch l?. The mechanism is preferably4arranged such that in operation, the switch finger ||2 is. engaged by.the

theV throttlev .valve in 'response to depression ofthe accelerator Mapproaches its full open `throttle position, sothat `'the switchP isclosed withnsnap laction during Vapproximately the last V5orysoof-"throttle open- It will beV understoodfthat the occur subsequentlto full `open vthrottle,position by' the provision ofv suitable lostmotion @mechanism such as disclosed inthe patent to Neracher etal.2,455,943. .When the; accelerator M is released, the finger .H0 comesintof contact :with the actuating finger |2 of vtheswitchnear the -iullyreleased position of *the accelerator to. actuate the switch P toitsopenpostorl, again by s napaction, the parts being vsov arranged thattheiswitch P win happened `by finger lloiwnen- .ever ,theacceleratorpcdal is fullyhreleased.

The ignition mechanism Vgenerally designated by theletter J is .ofconventional type and includes an ignition coil.|.20, a distributor;.I22,'and a breaker |24. Groundingof .the ignition, lfor torque reliefis obtained undercontroltof a normally open ignition .interrupting.controlA Switch having terminals 30, y.| 3 l, the .latter of; .whichconnects by a conductor |32 with the terminal 85 of the governor switchN providing a ground 88 for vthis relay, the terminal 8,5 being a commonterminal for conductor 90, and 84, the former extending to thel kickdownswitch P providing a ground 94 and the latter to the valvesolenoid L.

As noted above, prior control structures providing the valve solenoidand ignition primary winding in parallel arranged circuits made itpossible for the solenoid to function as a parallel impedance of lowvalue to the primary winding and weaken the spark delivered by thesecondary at the spark plug |35 when current flow thereto took place.

A feature of the present invention is to overcome this difficulty and toaccomplish this I provide between the coil |20 and circuit breaker |24of the ignition mechanism J and the ignition interrupting control switchT, a control relay R which I may for convenience, term an impedancecontrol relay so arranged that its own winding will not function as didthe valve solenoid L previously. This relay will preferably function topermit ignition interruption during a normal governor or acceleratorcontrolled downshift but not during normal upshifts by governor oraccelerator control and further will prevent a circuit being establishedbetween the solenoid L and the circuit breaker points distributorpoints), during upshifting when the interrupter switch is manipulated toclose momentarily, thereby preventing the solenoid L from producing theundesirable impedance effect above noted. y

The relay R comprises a normally open ignition interrupting switch |31and solenoid |38. The latter is connected by a conductor |39 withterminal |30 of the ignition interrupting control switch T and by aconductor |40 with conductor 8| of the battery side of the circuiting.It will be observed that the solenoid |38 will be energized to effectmovement of the switch arm 14| to close ignition interrupting switch |31whenever the governor switch N or the kickdown switch P is closed. 'Iheignition interrupting switch |31 has a terminal |42 connecting with aground |43 by a conductor |44 and has a switch terminal |45 thatconnects bya conductor |46 with a conductor |48 connecting the primarywinding |26 and the circuit breaker |24.

Whenever the solenoid |38 is energized by closing of ignitioninterrupting control switch T at a time when either Vthe governor switchN or kickdown switch Pis also closed, the ignition interrupting switch|31 will be actuated to closed position to apply the ground |43 to theprimary winding |26 and thereby ground the ignition. When the solenoid|38 is again deenergized, the ignition interrupting s 'tch |31 will beopened by opening |50 to reestablish the ignition.

When the ignition interrupting control switch T is momentarily closedduring upshift, the solenoid |38 will not be energized since at thistime neither of switches N nor P are closed. Moreover, at `this time itis impossible for parallel closed circuits to be established frombattery to the breaker points |36 through the primary winding andthrough the solenoid L or the solenoid |38.V Hence there will be no lossof current flow from the secondary winding to the spark plugs |35.

It will be noted skirt |60 reduced at.

that thepiston 31 has its outer |6| adjacent the cammed l portions |62,l|63 fori controlling operation of the |36 (sometimes called ignitioninterrupting control switch T. This switch is biased to open position bya spring |64 and has its operating stem engaging a ball |66 so arrangedin association with the piston portion |60 that switch T is open whenthe piston is in the Figure 2 position and in the Figure 3 position offorward movement of the piston. However, as the cammed portions |62, |63move by the ball |66 in either direction of movement of the piston, theball |66 is actuated to close the switch T. Thus, for example, in theforward movement of the piston the cammed portion |62 operates the ballto close the switch and the cammed portion |63 permits the ball toreturn the switch to open position the ball |66 dropping in the reducedportion |6| of the piston, as seen in Figure 3. On the downshiftingmovement of the piston from that shown in Figure 3, the cammed portion|63 actuates the ball |66 to close the switch T and the cammed portion|62 permits the ball to return to the open position of the switch T.

The operation of the transmission and control system will now bedescribed. kLet it be assumed that the vehicle is at a standstill withthe manual sleeve F shifted forwardly in engagement with the teeth 26 ofthe third speed gear 22 as seen in Figure 2. At this time the governorswitch N will be closed and provides a circuit from the battery 15 tothe ground 98 by way of the conductors 18, 8| and the solenoid L, thusenergizing the latter whereby the solenoid rod 12 maintains the ball 69of the valve K in its down position venting the motor H so that thespring 49 holds the piston 31 and the clutch sleeve D in the positionshown in this figure. The ignition interrupting control switch T is openas shown, the ball operator |66 thereof being free of the skirt |60 ofthe piston 31. The switch |31 of the relay R is open since the solenoid|38 is deenergized, the ignition interrupting control switch T beingthen open. The kickdown switchv P is open since the accelerator pedal isreleased.

By depressing the accelerator Apedal within its normal operating range,the vehicle is driven in third speed ratio drive. Atsome predeterminedspeed of vehicle travel, forv example 12 to 14 M. P. H. (6 to 7 M. P. H.in iirst speed), the governor O actuates the switch N to open positionthus breaking the circuit between the ground 88 and the conductor 84.The solenoid L is thereupon deenergized and the valve K closed byoperation of the spring 68 which moves the ball 69 of the valve to closethe port 10 at the entrance of the return passage 1|, thus permittingpressure to be built up bylthe pump Q in the passage 66. At the'momentof operation of the solenoid L the ignition interrupting control switchT is in the relay switch v|31 in open position as shown in Figure 2.When the uid pressure in the passage 66 builds up sufficiently, thepiston 31 moves forwardly for'its upshift stroke and comes to rest atthe position shown in Figure 3 where thev relief port 48`is uncovered bythe piston to relieve fluid pressure in excess of that required tomaintain the piston at this position. 4

During forward movement of the piston 31,7the springs 46 and 49'arecompressed.` Initially the spring 46 moves the motion transmitting meansS and thereby the sleeve D to its blocked position against the'blocker'E; Thenlost motion movementtakes place between the piston 31 and the,shift rail 38 'during .which the springs 46 and y49 continue tocompress. During the lost motion movement, the skirt |60. of the pistonhas its cammed portion |62 move past the ballV |66 of the switch Tcamming the ball |66 upwardly to close this switch, the switch Tremaining closed until the cammed portion' |63 of the skirt |66 passesunder the ball |66 at which time the ball drops into the recess orrelief portionv |6| of the piston to reestablish the switch T in openposition. Thereafter', upon accelerator release to synchronize thespeeds of the sleeve D and the clutch teeth I6, the sleeve D is movedby' the spring 46 acting upon the yoke 4|v of the motion transmittingmeans S, to its engaged position shown in Figure 3. During this engagingmovement, the rail 38 moves forwardly relative to the piston 37, thelatter remaining in its position shown in Figure 3, uncovering the port48.

Although the ignition interrupting control switch T'is operated duringthe forward movement of the piston 37, the spark'delivered by thesecondary winding |5| of the ignition system at the plugs |35 is neitherinterrupted nor weakened for the reason that the governor switch N andthe kickdown switch P are open and. therefore the solenoid |36 of therelay'RV is deenergized and the switch |37 thereof is open. Thus theground |43 is not available for interrupting the ignition system, nor isit possible for the solenoid L and the primary winding |26 to besimultaneously subjected to current iiow in parallel circuits from thebattery having as a common ground terminus the breaker points |36.Neither is it possible for the solenoid |38 itself and the primarywinding |26 to be conditioned for current flow in parallel series havingas a common ground the breaker points |36.

Once established in` fourth speed, a downshift to 'hird speed iseifected either by kickdown switch P by means of the accelerator pedal Mor ample, when the driver desires t`o manually effect the downshift fromfourth speed to third speed, he fully depresses the accelerator pedal M.During thisv operation, for example, as the throttle approaches its fullopen position, the switch P -is closed. Since the engine is thendelivering its full power, it is desirable to effect torque relief atthe teeth I6 to facilitate the release of sleeve D for the downshift. Atthis time the switch T is in its Figure 3 open position with the'ball|66 in the recess |61 ofthe piston which is then in its positionadjacent the relief port 48. Morein Figure 3, and the'relay switch |37is in its open position. Closing of the switch P' applies the ground 63to the solenoidL circuit from the battery 75 causing energization of thesolenoid' L and opening of the'valve K to vent the mot'or'H.

drop rapidly allowingthe'piston 37 to commence its rearwardV movementvunder biasv of the spring 49.

As noted above, the ignition interrupting control switch T is in serieswith the solenoid |39 of the relay R whose ignition interrupting switch|37 controls the ground |43 for thel ignition primary winding. Moreover;it has been stated that when pressure is vented in the cylinder 36 ofthe motor H, the; clutch sleeverDusually initially remains engagedlwith'theteeth 6 while-"the piston 37 begins its return movement? under urgingof the spring '49,I by reason of theengine torque load on the-teeth.lHence, the piston 37 will usually initially take up the lost motionmovement 5| between itself and the shoulder 52 of the end portion 53 ofthe rail 36. During this lost motion movement the cammed portion |63 ofthe piston moves under the ball |36 of the switch T thereby urging theball |66 upwardly to close the switch T and complete a circuit frombattery through the solenoid |38 of the relay R to the ground 93 `of thekickdownswitch P. Energization of the solenoid |38 causes the switch |37of the relay R toY close thereby completing' the circuit between theprimary winding |26 of the ignition coil |20 and the ground |43 therebygrounding theignition system. The engine now missing nre, unloadsthetorque load on the teeth of the sleeve D thereby permitting thespring #i6 to effect disengagement ofthe sleeve D by moving the piston37 and rail 38 further rearwardly and complete the rearward or returnmovement of the sleeve D,-piston 3-7 and rail 36 to the position shownin-Figure 2. During this return movement the cammed portion |62 of thepiston passes beneath the ball |66 of the switch T permitting the latterto return to its openV position restoring the ignition.` to normaloperation. When subsequently the accelerator pedal M is releasedsuiciently to open the switch P, fourth speed ratio drive may againberestored as previously described` provided the vehicle speed is stillsuch that the governor switch N is open.

For the automatic downshift from fourth speed to third speed undercontrol of the vehicle governor O, it is only necessary to reduce thevehicle speed to or below the speed at which the governor switch Nnormally closes. Closing of the switch N energizes the solenoid L bycompleting a circuit from the battery to the ground 68. The motor H isthen vented and the interrupter switch T operated to effect energizationof the solenoidV |38 and closing of switch |37 to ground the ignition,all as there described.

When the sleeve F' is in its rearward or low range position, the upshiftand downshift movement of the sleeve D between rst and second speedpositions will be the same as that set forth for the operation of thissleeve between third and fourth speed positions when the sleeve F is inits high range setting; However, since the governor O is driven from thecountershaft as at |60, |6| in Hgure 2, the governor O will function ata somewhat lower car speed depending upon the gear ratios for first andsecond speed as compared with third and fourthv speed as: will bereadily understood. It will be noted, however, that the governor drivingmeans-IUI may, if desired, be on the driven shaft I4.

From the foregoing description of my invention it will be apparentlthatI have provided a novel ignition interrupter` control system andstructure for. transmissions. having both governor and manuallycontrolled downshifting wherein ignition interruption for disengagingengaged lclutch elements is obtained as required, and operation oftheinterrupter means during upshifting operations will not in normaloperation of the vehicle cause interruption of the ignition system norwill operation of the interruptor switch during upshifting at any timecause weakening of the spark delivered by the secondary winding of theignition coil at the spark plugs, at the time of current ow thereto.

It will also be apparent that the invention is applicable to .Otherformsof transmissions. More- 13 over, although: the disclosed v embodiment.of the invention is well adapted for carrying out the objects`hereinabove set forth, it willbe understood that various modifications,changes and substitutions coming within the spiritv of my invention andwithin. the scope of the appended claims are also contemplated.

I claim:

l. Ina power transmission for driving a vehicle having an engineprovided with an ignition system having a primary winding; a shiftabletransmission drive control. element shiftablefrom a first positiondisengaged relative to another drive control element to a secondposition of.` engagementwith said other element and. shiftable out ofsaid second positionwhen operation ofsaid ignition system is momentarilyinterrupted to relieve the thrustload at said shiftable element, meansfor effecting. shift of said shiftabledrive control element between itsVtwo said positions, electromagnetically operable l means. forcontrolling said shift effecting means, ignition interrupting controlswitch meansoperable by said shift effecting means when effecting shiftof said shiftable drive control element between said first and secondpositions, ground applying switchA means in series electrically withsaid electromagnetically operable means and with said ignitioninterrupting control switch means, and a relay for controlling ignitioninterruption including a solenoid electricallyA in series with saidignition interrupting control switch means and an ignition interruptingswitch controlled by said solenoid and in series electrically with saidprimary winding for interrupting the ignition system.

2.In.a1power transmission for driving a vehicle having anengine providedwith an ignition system including a primary ignition winding and breakercontacts electricallyl inseries; a shiftable transmission drive controlelement shiftable from a rst position disengaged relative to anotherdrive control element to a second position of engagement with` saidother elementv and shiftable out of said second position when operationof said ignitionV system is momentarily interrupted to relieve thethrust load at said shiftable element, means foreiecting shift of saidshiftalble drive control element between its two said positions,electromagneticallyV operable means for controlling said shift effectingmeans, switch. means for controlling said electromagnetically operablemeans and arranged in series electrically therewith, a relay for'controlling ignition interruption, said relay including a ground switchoperable for applying a ground to said primary ignition winding for.interrupting the. ignition, and other switch means operable by saidshift effecting means for controlling said relay, said other switchmeans being in series electrically with said relay and said firstmentioned switch means.

3. In a power transmission for driving a vehicle having an engineprovided with an ignition system including a primary ignition windingand breaker contacts electrically in series; a shiftable transmissiondrive control element shiftable from a first position disengagedrelative to another drive control element to a second position ofengagement with `said other element` and shiftable out of. said secondposition-.when operation of said ignition system is momentarilyinterrupted to relieve the thrust load at said shiftable element, meansfor effecting shift of said shiftable drive control element Ibetween itstwo said positions, electromagnetically operable means for controllingsaid shift effecting means, speed responsiveswtch means for controllingsaid electromagnetically operable means andy arranged` in serieselectrically therewith, a relay for controlling ignition interruption,sad relay including ay ground. switch operable. for applying a ground tosaid. primary ignition windingv for interrupting the ignition, and otherswitch means operable. by said shift effecting means for controllingsaid .relay, said. otherl switch vmeansbeing inseries electrically withsaid relay andsaid first f mentioned switch means..

4..In .a power transmission for driving a vehicle having` anengineprovided with an ignition system including a'primary. ignitionwinding` and breaker contacts electricallyv in series; a shiftabletransmission. drive control elementshiftable froma firstv position.disengaged relative to another drive control element to a secondpositionof engagement-with said othery element and shiftable out .of said secondposition whenoperation of said ignition system is momentarilyinterrupted to relieve the thrust load at said shiftabl-e element,meansfor eifecting shift of said shiftable drive control-element betweenits two said positions, electromagnetically operable means forcontrolling said shift effectingV means, accelerator operablev switchmeans for controlling, said electromagnetically operable means. andarranged in series electrically therewith, a relay for controllingignition interruption,` said relay including a ground switch operablefor applyingV a ground to said primary ignition winding for.interrupting'the ignition, and other switch means operable by said shifteffecting means for oontrolling said relay, said other switchmeanszbeing inseries electrically with said relayy and said firstmentioned-'switch means. y

5. In a power transmission for driving a. vehicle having, an engineprovided with an. ignition system including a primary ignition windingand breaker contacts electrically in series; a shiftable transmissiondrive control element shiftable from a first position disengagedrelative to another drive control element to a second position ofengagement with said otherxelement' and. shiftable out of said secondlposition when operation. of saidv ignition system is momentarilyinterrupted to relieve the thrust load at said shiftable` element, meansforeffecting. shift'of said shiftable drive control element betweenk itstwo said positions, electromagneticallyl operable meansY for controllingsaid shift effecting means, speed responsiveswitch means and driveroperable switch means for controlling said electromagnetically operablemeans and arranged in serieselectrcally therewith and in `parallelelectrically with each other, a relay' for controlling ignition,interruption, said relay including a ground switch .operable forapplyingaground to. saidprimary ignition winding for interruptingy theignition, and other switch means operable by said shift-effecting meansvfor controlling. said' relay, said other switch means being.l inserieselectrically with said relay and said. rst mentioned 'switch means.-

6. In a power transmission for.V driving a vehicle having an engine.provided 4with anignition system-including a primary ignition windingand breaker contacts electrically in. series; avshiftable'transmissiondrive control element shiftable from a firstposition. disengaged relative to another drive control elementito avsecond position of engagement .with said other elementand shiftable outof said second position when operation of 4said ignition system ismomentarily interrupted to relieve the thrust load at said shifta'elgeioable element, meansfor effecting shift of said shiftable drive controlelement between its two said positions, electromagnetically operablemeans for controlling said shift effecting means, switch means forcontrolling said electromagnetically operable means, said switch meanshaving an open and a closed position and operable when closed forenergizing said electromagnetic, means, a relay for controlling ignitioninterruption, said relay including a ground switch and a solenoid, saidgrounding switch being operable when closed for applying a ground tosaid primary `winding for interrupting the ignition, and said relaysolenoid being operable when energized for closing said groundingswitch, and an interruption controlling switch having an open positionand a closed position to which it is operable by said, shift effectingmeans, said switch being electrically in series with said solenoid andsaid switch means and when closed when said switchmean-s is in closedposition being operable for energizing ysaid solenoid.

7. In a power transmission for driving a vehicle having an engineprovided with an ignition system including a primary ignition windingand breaker contacts-electrically in series; a shiftable transmissiondrive control element shiftable from a rst position disengaged relativeto another vdrive control element to a second position of engagementwith said other element and shiftable out of said second position whenoperation of said ignition system is momentarily interrupted to relievethe thrust load at said shiftable element, motion transmitting means forshifting said shiftable drive control element, differential pressureoperable motor means including a piston, operable upon said motiontransmitting means for effecting shift of said shiftable drive controlelement between its two said positions by said motion transmittingmeans, electromagnetically operable means for controlling said shiftefle'cting means, switch means for controlling said electromagneticallyoperable means and arranged in series electrically therewith, a relayfor controlling ignition interruptiomsaid relay including a groundswitch operable for applying aV ground to said primary ignition windingfor interrupting the ignition, and other switch means operable by saidpiston for controlling said relay, said other switch means being saidrelay and said rst mentioned switch means.

8. In a power transmission for driving a vehicle having an engineprovided with an ignition system including a primary ignition windingand breaker contacts electrically in series; a shiftable transmissiondrive control element shiftable from a rst position disengaged relativeto another drive control element to a second position of engagement withsaid other element and shiftable out of said second position whenoperation of said ignition system is momentarily interrupted to relievethe thrust load at said shiftable element, motion transmitting means forshifting said shiftable drive control element, differential pressureoperable motor means including a piston, operable upon said motiontransmittingmeans for effecting shift of said shiftable drive controlelement between its two said positions by said motion transmittingmeans, electromagnetically operable means for controlling said shifteffecting means, switch means for controlling said electro-.magnetically operable means, said switch means in series electricallywith having an open and a closed position and operable when closed forenergizing said electromagnetic means, a relay for controlling ignitioninterruptionsaid relay including a grounding switch and a solenoid, saidgrounding switch being operable when closed for applying a ground tosaid primary winding for interrupting the ignition, and said relaysolenoid being operable when energized for closing said groundingswitch, and an interruption controlling switch having an open positionand a closed position to which it is operable by said piston, saidswitch being electrically in series with said solenoid and said switchmeans and when closed when said switch means is in closed position beingoperable for energizing said solenoid.

9. In a power transmission for driving a vehicle having an engineprovided with an ignition system including a primary ignition windingand breaker contacts electrically in series; a shiftable transmissiondrive control element shiftable from a rst position disengaged relativeto another drive control element to a second position of engagement withsaid other element and shiftable out of said second position whenoperation of said ignition system is momentarily interrupted to relievethe thrust load at said shiftable element, motion transmitting means forshifting said shiftable drive control element, differential pressureoperable motor means including a' piston, operable upon said motiontransmitting means for effecting shift of said shiftable drive controlelement between its two said positions by said motion transmittingmeans, a valve for controlling said shift effecting means, a solenoidfor controlling said valve, speed responsive and driver operable switchmeans for controlling said valve solenoid, said switch means having openand closed positions and operable when closed for energizing said valvesolenoid, a relay for controlling ignition interruption, said relayincluding a grounding switch and a solenoid, said grounding switch beingoperable when closed for applying a ground to said primary winding forinterrupting the ignition, and said relay solenoid being operable whenenergized for closing said grounding switch, and an ignitioninterrupting control switch means electrically in series with said relaysolenoid and said speed responsive and manually operable switch means,said control switch means having an open and a closed position and beingmomentarily operable by said piston to closed position when electingshift of said shiftable drive control element between said first andsecond positions and again between said second and rst positions, saidcontrol switch means when closed being operable to energize said relaysolenoid only when said speed responsive and manually operable switchmeans is in closed position.

Louis n. FORMAN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS

